Southwest’s third quarter earnings release touted some good headline numbers about revenue, less so profit, but immediately it was clear that the story on whether changes like seat fees and bag fees were working was ambiguous at best.

However their SEC 10-Q filing is now available and the picture gets even a bit murkier. That’s because Southwest Airlines reported $428 million in adjusted pretax profit for the third quarter – however,

Aircraft and engine transactions produced $214 million of the gains, and sale/leaseback of aircraft are notoriously tricky. An airline can sell a plane for more than its worth, book profits, and just commit itself to higher lease payments in the future.

They changed their assumptions about how much resale values are for aircraft, and cut their depreciation expense by another $48 million.…